[8.19] Generate a test dependencies file to support unit tests in entitlements (#127486)

build-tools/build.gradle

@@ -51,6 +51,10 @@ gradlePlugin {
           id = 'elasticsearch.stable-esplugin'
           implementationClass = 'org.elasticsearch.gradle.plugin.StablePluginBuildPlugin'
         }
+        testBuildInfo {
+          id = 'elasticsearch.test-build-info'
+          implementationClass = 'org.elasticsearch.gradle.test.TestBuildInfoPlugin'
+        }
         javaRestTest {
             id = 'elasticsearch.java-rest-test'
             implementationClass = 'org.elasticsearch.gradle.test.JavaRestTestPlugin'

build-tools/src/integTest/groovy/org/elasticsearch/gradle/test/TestBuildInfoPluginFuncTest.groovy

@@ -0,0 +1,63 @@
+package org.elasticsearch.gradle.test
+
+import com.fasterxml.jackson.databind.ObjectMapper
+
+import org.elasticsearch.gradle.fixtures.AbstractGradleFuncTest
+import org.gradle.testkit.runner.TaskOutcome
+
+class TestBuildInfoPluginFuncTest extends AbstractGradleFuncTest {
+    def "works"() {
+        given:
+        file("src/main/java/com/example/Example.java") << """
+            package com.example;
+
+            public class Example {
+            }
+        """
+
+        file("src/main/java/module-info.java") << """
+            module com.example {
+                exports com.example;
+            }
+        """
+
+        buildFile << """
+        import org.elasticsearch.gradle.plugin.GenerateTestBuildInfoTask;
+
+        plugins {
+            id 'java'
+            id 'elasticsearch.test-build-info'
+        }
+
+        repositories {
+            mavenCentral()
+        }
+
+        tasks.withType(GenerateTestBuildInfoTask.class) {
+            componentName = 'example-component'
+            outputFile = new File('build/generated-build-info/plugin-test-build-info.json')
+        }
+        """
+
+        when:
+        def result = gradleRunner('generateTestBuildInfo').build()
+        def task = result.task(":generateTestBuildInfo")
+
+
+        then:
+        task.outcome == TaskOutcome.SUCCESS
+
+        def output = file("build/generated-build-info/plugin-test-build-info.json")
+        output.exists() == true
+
+        def location = Map.of(
+            "module", "com.example",
+            "representative_class", "com/example/Example.class"
+        )
+        def expectedOutput = Map.of(
+            "component", "example-component",
+            "locations", List.of(location)
+        )
+        new ObjectMapper().readValue(output, Map.class) == expectedOutput
+    }
+}

build-tools/src/main/java/org/elasticsearch/gradle/plugin/BasePluginBuildPlugin.java

@@ -121,7 +121,10 @@ private TaskProvider<Zip> createBundleTasks(final Project project, PluginPropert
             task.getIsLicensed().set(providerFactory.provider(extension::isLicensed));
 
             var mainSourceSet = project.getExtensions().getByType(SourceSetContainer.class).getByName(SourceSet.MAIN_SOURCE_SET_NAME);
-            FileCollection moduleInfoFile = mainSourceSet.getOutput().getAsFileTree().matching(p -> p.include("module-info.class"));
+            FileCollection moduleInfoFile = mainSourceSet.getOutput()
+                .getClassesDirs()
+                .getAsFileTree()
+                .matching(p -> p.include("module-info.class"));
             task.getModuleInfoFile().setFrom(moduleInfoFile);
 
         });